Genetic testing for FAP

Last Modified: August 28, 2005

Dear OncoLink "Ask The Experts," My family has familial adenomatous polyposis (FAP) on my mom's side. My mom has an ostomy & my brother had colon cancer 3 or 4 yrs ago. When he found out he had cancer, all of his siblings got a scope done. I had a colonoscopy done 2 yrs ago which came back normal, but my doctor wants to do genetic testing.

I guess my question is how many people actually consider genetic testing? I have never had to make such a tough decision. There are pros & cons to both sides, but after thinking about it for 2 yrs I am leaning on getting it done. What is involved in having it done? Is it just taking blood or what?

This is a very difficult decision to make. I am not sure if you have already done so, but anyone considering genetic testing should meet with a genetic counselor. Counselors are trained to present the pros and cons in an unbiased manner and follow through with the patient once the results are available.

One advantage to knowing your genetic testing results is that it can help guide your doctor's recommendations regarding what screening tests (scopes) you need and how often you need them. Without the results, your doctor may act very cautiously and advise you to have a colonoscopy every 2-3 years. However, if your physician knew that you did not have the gene that causes FAP, you may be able to have screening every 5-10 years, similar to the general public. Some researchers are concerned that if you find out that you do not have the gene, you may not be as motivated to have regular screening tests. You should understand that even if you do not have the FAP gene, you would still need to have colonoscopies, but just not as often. In addition, your results may have some effects on your other siblings or any children you have.

As you have realized, this is a difficult decision. I hope you can seek out the help of a genetic counselor in your area.